Victorian maths and science teachers are not required to be qualified to teach maths and science until VCE level.

Fewer than 10 per cent of VCE students took advanced maths in 2017, a 20-year low. Credit:The Age

“In Victoria, it’s mandated that a year 11 and 12 teacher must have a degree in mathematics, but if you’ve lost them [students] in year 7 and year 10 you’re not going to get them in year 12,” Professor Thomas said.

The percentage of Australian students enrolled in higher mathematics in year 12 fell to 9.4 per cent in 2017, its lowest recorded level in 20 years, according to a report by the Australian Mathematical Sciences Institute. In 2008, 10.3 percent of year 12 students did higher mathematics.

Meanwhile, Victoria has among the highest proportion of high school educators teaching subjects they are not qualified to teach, a 2016 study by the Australian Council for Educational Research found.

Thirty-two per cent of Victorian teachers taking classes between years 7 to 10 are not qualified to teach the specific subjects they are teaching, the study found, compared with a national average of 27 per cent.

Dr Linda Hobbs, Associate Professor of Education at Deakin University, said in Victorian schools it was often up to the principal to decide who taught maths and science in years 7 to 10, while NSW placed a greater focus on giving out-of-field teachers additional training.

“There is a culture in Victoria that ... a good teacher can teach anything,” she said. “There is an undercurrent of truth in that but it sets aside the value of a grounding in knowledge.”

The most recent international assessment of Australia’s academic performance against other nations put Australian students above the OECD average, but listed it as one of 10 nations that experienced a sharp decline in mathematical literacy between 2012 and 2015.

But Associate Professor Hobbs cautioned that data did not show a strong link between out-of-field teaching and student achievement.

Wendy Powson, principal of Lilydale High School, said she knew of a number of schools in her area that struggled to find qualified maths and science teachers.

“One has advertised a number of times and not attracted one applicant,” Ms Powson said.

Another has often been forced to fill the position with a teacher who is not qualified in that subject.

“The teacher maybe has good relationships with kids and good classroom management but their expertise is not actually teaching maths and science,” Ms Powson said.

Mark Grant, chief executive of the Australian Institute for Teaching and School Leadership said the extent of out-of-field teaching in Australia is not well understood, as there is no national data.

Mr Grant said professional standards for teaching required teachers to know the content of what they teach and how to teach it.

“Teachers who find themselves teaching out of field require support to ensure they are properly equipped to handle this challenge,” he said.

Education Minister James Merlino said the state government knew that out-of-field teaching in specialist subjects such as maths and science was a challenge for schools.

“That’s why we are investing to attract high quality teachers through the new $17.9 million STEM Catalyst Program to provide out-of-field secondary teachers with specialised training in mathematics and science,” Mr Merlino said.